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| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2018-01-18 15:42:09 -0500 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2018-01-18 15:45:48 -0500 |
| commit | 0164e0d7e803af3ee1c63770978c728f8778ad01 (patch) | |
| tree | 0bcf3a618d4d36a1efc6458456f579783b17d19e | |
| parent | 68e76e034b6b1c1ce2eece1ab8ae4008e14be470 (diff) | |
| download | lwn-0164e0d7e803af3ee1c63770978c728f8778ad01.tar.gz lwn-0164e0d7e803af3ee1c63770978c728f8778ad01.zip | |
ring-buffer: Fix duplicate results in mapping context to bits in recursive lock
In bringing back the context checks, the code checks first if its normal
(non-interrupt) context, and then for NMI then IRQ then softirq. The final
check is redundant. Since the if branch is only hit if the context is one of
NMI, IRQ, or SOFTIRQ, if it's not NMI or IRQ there's no reason to check if
it is SOFTIRQ. The current code returns the same result even if its not a
SOFTIRQ. Which is confusing.
pc & SOFTIRQ_OFFSET ? 2 : RB_CTX_SOFTIRQ
Is redundant as RB_CTX_SOFTIRQ *is* 2!
Fixes: a0e3a18f4baf ("ring-buffer: Bring back context level recursive checks")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| -rw-r--r-- | kernel/trace/ring_buffer.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 0cddf60186da..5af2842dea96 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2579,8 +2579,7 @@ trace_recursive_lock(struct ring_buffer_per_cpu *cpu_buffer) bit = RB_CTX_NORMAL; else bit = pc & NMI_MASK ? RB_CTX_NMI : - pc & HARDIRQ_MASK ? RB_CTX_IRQ : - pc & SOFTIRQ_OFFSET ? 2 : RB_CTX_SOFTIRQ; + pc & HARDIRQ_MASK ? RB_CTX_IRQ : RB_CTX_SOFTIRQ; if (unlikely(val & (1 << bit))) return 1; |